The present invention relates to a mechanically controlled brake booster for a motor vehicle which utilizes the pressure difference between a vacuum and the atmospheric pressure and which essentially includes a vacuum housing or casing with at least one movable wall arranged therein and a pressure control valve provided with a control housing or casing. The movable wall, which is provided with a hub, divides the vacuum casing into a vacuum chamber and a working chamber and, by means of cross members acts on a push rod guided in the axial direction of the brake booster. A pipe or tube is arranged in the vacuum casing which at least approximately extends in the axial direction and is connected to the end walls of the vacuum casing. The tube is provided with at least two longitudinal slots and the movable wall is sealed and displaceable relative to the pipe.
Such a brake booster is disclosed in the copending U.S. patent application of J. Belert-F. Wienecke, Ser. No. 61,113, filed July 16, 1979, assigned to the same assignee as the present application, whose discosure is incorporated herein by reference. This application provides a brake booster in which the material costs and the weight are considerably reduced as compared with known brake boosters.